1. Field of the Invention
The present invention relates to a charge control device for a vehicle, and particularly to a charge control device for a vehicle that is configured to be capable of charging a power storage device used for driving the vehicle, with electric power from a power supply outside the vehicle.
2. Description of the Background Art
An electric-powered vehicle is mounted with a power storage device (such as secondary battery or capacitor for example) and travels by using driving force generated from electric power stored in the power storage device. The electric-powered vehicle includes, for example, electric vehicle, hybrid vehicle and fuel-cell vehicle.
In recent years, a technique has been proposed for charging a power storage device mounted on such electric-powered vehicles as described above by a commercial power supply having a high power generation efficiency. With this technique, increase in fuel consumption efficiency of the hybrid vehicle for example can be expected. In particular, attention is given to a technique for charging a power storage device mounted on an electric-powered vehicle by a commercial power supply providing electric power to each household (a source of a relatively low voltage such as 100 V or 200 V, for example). In the following, a vehicle having a power storage device such as a battery mounted on the vehicle and configured to be chargeable by an external power supply for the vehicle is also referred to as “plug-in vehicle.”
A technique has heretofore been proposed that is used for detecting an abnormality occurring while a power storage device mounted on a vehicle is charged. For example, Japanese Patent Laying-Open No. 2000-270484 discloses an abnormality detection device capable of detecting an abnormality such as a break of a commercial power supply line or power failure. The abnormality detection device can detect an abnormality as described above after charging of an electric-powered vehicle is started.
Standards for the plug-in vehicle are established in the United States by “SAE Electric Vehicle Conductive Charge Coupler” (“SAE Electric Vehicle Conductive Charge Coupler,” (US), SAE Standards, SAE International, November 2001), and established in Japan by “General Requirements for Electric Vehicle Conductive Charging System” (“General Requirements for Electric Vehicle Conductive Charging System,” Japan Electric Vehicle Association Standard (Japan Electric Vehicle Standard), Mar. 29, 2001).
“SAE Electric Vehicle Conductive Charge Coupler” and “General Requirements for Electric Vehicle Conductive Charging System” define standards regarding for example a control pilot. The control pilot is defined as a control line connecting a control circuit for an EVSE (Electric Vehicle Supply Equipment) which supplies electric power from an on-premises power line to a vehicle and a ground portion of the vehicle via a vehicle-side control circuit. Based on a pilot signal transmitted via the control line, the state of connection of a charge cable is detected, whether or not electric power can be supplied from a power supply to the vehicle is determined, or the rated current of the EVSE is detected, for example.
“SAE Electric Vehicle Conductive Charge Coupler” and “General Requirements for Electric Vehicle Conductive Charging System,” however, do not particularly define details of how to detect a break of the control line through which the pilot signal is transmitted. For example, from the mere fact that the potential of the control line is at the ground level, it cannot be determined whether the control line is broken, failure of power supply occurs or a charge cable is unintentionally disconnected from a receptacle. In the following, an abnormality in electric power supply to a vehicle, such as failure of power supply and unintentional disconnection of the charge cable from a receptacle, for example, is referred to as “power-supply-side abnormality.”
The pilot signal is a requisite signal for controlling charging of the plug-in vehicle as described above. It is therefore extremely important for the plug-in vehicle to detect an abnormality in the pilot signal, especially detect a break of the control line through which the pilot signal is transmitted.
The abnormality detection device disclosed in Japanese Patent Laying-Open No. 2000-270484 cannot detect an abnormality unless the commercial power supply is connected to the vehicle. This abnormality detection device is therefore considered to be capable of detecting a power-supply-side abnormality only.